以下是Yuda Prawira的回答:

实现flush()和所有文件属性 将其编写为上下文管理器 也捕获stderr

.

import contextlib, sys

@contextlib.contextmanager
def log_print(file):
    # capture all outputs to a log file while still printing it
    class Logger:
        def __init__(self, file):
            self.terminal = sys.stdout
            self.log = file

        def write(self, message):
            self.terminal.write(message)
            self.log.write(message)

        def __getattr__(self, attr):
            return getattr(self.terminal, attr)

    logger = Logger(file)

    _stdout = sys.stdout
    _stderr = sys.stderr
    sys.stdout = logger
    sys.stderr = logger
    try:
        yield logger.log
    finally:
        sys.stdout = _stdout
        sys.stderr = _stderr


with log_print(open('mylogfile.log', 'w')):
    print('hello world')
    print('hello world on stderr', file=sys.stderr)

# you can capture the output to a string with:
# with log_print(io.StringIO()) as log:
#   ....
#   print('[captured output]', log.getvalue())

基于这篇文章之前的回答，我为自己编写了这个类，作为一种更紧凑和灵活的方式来重定向代码段的输出——这里只是一个列表——并确保之后的输出是规范化的。

class out_to_lt():
    def __init__(self, lt):
        if type(lt) == list:
            self.lt = lt
        else:
            raise Exception("Need to pass a list")            
    def __enter__(self):
        import sys
        self._sys = sys
        self._stdout = sys.stdout
        sys.stdout = self
        return self
    def write(self,txt):
        self.lt.append(txt)    
    def __exit__(self, type, value, traceback):
        self._sys.stdout = self._stdout

用作:

lt = []
with out_to_lt(lt) as o:
    print("Test 123\n\n")
    print(help(str))

更新。刚刚发现了一个场景，我必须添加两个额外的方法，但很容易适应:

class out_to_lt():
    ...
    def isatty(self):
        return True #True: You're running in a real terminal, False:You're being piped, redirected, cron
    def flush(self):
        pass

import sys
sys.stdout = open('stdout.txt', 'w')

根据这个答案:https://stackoverflow.com/a/5916874/1060344，这是我在我的一个项目中使用的另一种方法。无论你用什么替换sys。Stderr或sys。stderr/ Stdout被用在一些不受你控制的库中，你必须确保替换符合文件接口，特别是当你这样做的时候。该库可能正在使用文件对象的其他方法。

以这种方式检查，我仍然让所有内容都执行stderr/stdout(或任何文件)，并使用Python的日志记录功能将消息发送到日志文件(但你真的可以用它做任何事情):

class FileToLogInterface(file):
    '''
    Interface to make sure that everytime anything is written to stderr, it is
    also forwarded to a file.
    '''

    def __init__(self, *args, **kwargs):
        if 'cfg' not in kwargs:
            raise TypeError('argument cfg is required.')
        else:
            if not isinstance(kwargs['cfg'], config.Config):
                raise TypeError(
                    'argument cfg should be a valid '
                    'PostSegmentation configuration object i.e. '
                    'postsegmentation.config.Config')
        self._cfg = kwargs['cfg']
        kwargs.pop('cfg')

        self._logger = logging.getlogger('access_log')

        super(FileToLogInterface, self).__init__(*args, **kwargs)

    def write(self, msg):
        super(FileToLogInterface, self).write(msg)
        self._logger.info(msg)

如果您想在Python脚本中进行重定向，请设置sys. exe。对文件对象的Stdout是有用的:

# for python3
import sys
with open('file', 'w') as sys.stdout:
    print('test')

一个更常见的方法是在执行时使用shell重定向(在Windows和Linux上相同):

$ python3 foo.py > file

你可以尝试更好的方法

import sys

class Logger(object):
    def __init__(self, filename="Default.log"):
        self.terminal = sys.stdout
        self.log = open(filename, "a")

    def write(self, message):
        self.terminal.write(message)
        self.log.write(message)

sys.stdout = Logger("yourlogfilename.txt")
print "Hello world !" # this is should be saved in yourlogfilename.txt